JBL D-130s & Altec 511b horns...

[Zilch]

How soon will we (you) know something?

It's good. I'm listening to the 16-Ohm version on 811B right now. The compensation is a little different than for 8-Ohms on 511A. Still working that out. 511 sounds better at 800 Hz. 811's really a 1.2+ kHz horn; running it at 800Hz invokes some compromises.

I'll try to work through the various combinations tonight, and post the results....

 

[macaltec]

It's good. I'm listening to the 16-Ohm version on 811B right now. The compensation is a little different than for 8-Ohms on 511A. Still working that out. 511 sounds better at 800 Hz. 811's really a 1.2+ kHz horn; running it at 800Hz invokes some compromises.

I'll try to work through the various combinations tonight, and post the results....

Well, hurry up :dammit: inquiring minds wanna know .

 

[Redboy]

Zobel, you don't need right now. It's specific to each LF driver, and you're not certain you'll be keeping the D130s. Consider a Zobel a "refinement" at this point.

No special consideration for the fact that my horn drivers are rated 8 Ohms and the D130's are 16 Ohms?

Which reminds me, I wouldn't cut those ducts for your initial evaluation. Finding new material the correct diameter for the existing hole in the cabinets may not be so easy later, so save them, and fabricate the new 2" ones from a suitable alternative material, as the duct length will change for a different driver and tuning.

Good thought... Do they make PVC pipe in 5" D? :scratch2:

 

[Zilch]

No special consideration for the fact that my horn drivers are rated 8 Ohms and the D130's are 16 Ohms?

Your D130s are "indeterminate" until measured. JBL played fast and loose with impedance designations back then. Measure the DC resistance, and we can take a guess....

 

[Redboy]

Hey, I did that! Just leads on the terminals, right? Meter read 6 Ohms, which seemed weird to me for a 16 Ohm driver.

 

[Zilch]

Yup. I'd call them 8-Ohm drivers, but would do an impedance sweep to be certain. What that means is you're likely good to go woofer impedance-wise with your crossover selection.

I do have a couple of those in storage; maybe I dig them out later. Doing HF right now -- 811 horn results top two using different impedance drivers, 511 next two....

http://audioheritage.org/vbulletin/showthread.php?p=159290#post159290

I have more vintage Altec 806A drivers coming for measurement later this week; we'll see if they're really all that, well, "compromised" with respect to HF response.

[I'm afraid so. We have similar independent measurement results by others which we didn't believe....]

 

[Redboy]

I have more vintage Altec 806A drivers coming for measurement later this week; we'll see if they're really all that, well, "compromised" with respect to HF response.

Maybe the fact that mine are the 808-8a's will somehow work out in my favor... :scratch2:

Seems unlikely, since I don't know squat what makes the one different from the other. That usually doesn't bode well for me. :sigh:

Ordered those parts. Now I wait.

 

[cabinover]

Seems unlikely, since I don't know squat what makes the one different from the other. That usually doesn't bode well for me. :sigh:

QUOTE]

That's funny, you could be my brother. Sounds exactly like my luck:yes:

Keep at this guys, it's quite interesting. At least I know my hearing didn't take an overnight dive when I look at the HF graphs via the links.

 

[cabinover]

Zilch I have a question for you on your graphs in the link. According the gradient up the left side of the graphs these drivers/horn combo are capable of only 80-90dB. That's not correct is it?

I'm sure I'm missing something I just don't know what.
Thanks

 

[cabinover]

Edited for double post.

 

[macaltec]

I know my course of action at this point :yes: .

 

[cabinover]

You looking at those 4550 drivers Jason?

 

[macaltec]

You looking at those 4550 drivers Jason?

Yup! I heard the difference in response going from the 808-8A/806A to a Carvin driver (rebadged Eminence PSD2002). It's response is good out to 15K and the difference was very obvious. This promises to be even better. I'll be waiting for round two on the 806 measurements though.

*EDIT*In fairness, the 806A's seem to do a good job on the 511 with my A7's and I have only tried the Carvin on an 811 as it won't play low enough to mate well with the A7 bass bin.

 

[Zilch]

Zilch I have a question for you on your graphs in the link. According the gradient up the left side of the graphs these drivers/horn combo are capable of only 80-90dB. That's not correct is it?

I'm sure I'm missing something I just don't know what.
Thanks

No, that's just the level at which I measured them. The same level was applied to all drivers throughout the testing. They'll play WAY higher SPL than that.

I try to test at normal listening levels. The mic is at 1.5m. You can clearly see there that the BMS drivers, even compensated, put out more SPL than the stock Altecs. Thus, there is no problem of insufficient sensitivity or efficiency when it comes to mating them with high-sensitivity woofers....

 

[Zilch]

Seems unlikely, since I don't know squat what makes the one different from the other.

Fact is, nobody seems to know squat about vintage Altec drivers. Or, if they do, they have the decency not to post what they know. :

I believe Macaltec can tell you more about your drivers as relates to my measurements of 806As, since he has both types, apparently. I'll be pleased to measure them for you if you're willing to cover the costs of shipment to CA....

Ordered those parts. Now I wait.

HUH? Now's the time to tune your boxes and listen to their new bass!

 

[macaltec]

Fact is, nobody seems to know squat about vintage Altec drivers. Or, if they do, they have the decency not to post what they know. :

I believe Macaltec can tell you more about your drivers as relates to my measurements of 806As, since he has both types, apparently. I'll be pleased to measure them for you if you're willing to cover the costs of shipment to CA....

HUH? Now's the time to tune your boxes and listen to their new bass!

I'm scraping up some money to get the needed test equipment. Not that I don't believe Zilch, but more because if I expereince it first hand I will understand it more. That and this kinda thing is of much interest to me. I wonder though :scratch2: , have the Altec drivers you measured been remagnatized?????? None of mine have, The 806A's have never been opened and the 808-8A have new Radian 1228 diaphragms in them. Neither setup sounded bad (actually pretty good) when used on the 511 with the A7 bass bin, but both are painful (literally) on the 811. I don't want it to be so, but I think the 800 series drivers from Altec are lacking :tears: . Still holding on to hope that it ain't so :sigh: .

 

[cabinover]

I know that the A7 setup I heard sounded good to me. Then again it was massaged by our own Dwojo, with tweeter above at one of the past AKFests.

Beyond that all I know is what you're showing me here and that an 807/511B combo with an 800Hz crossover doesn't cut it with my ear.

While you may be stepping on toes here, carry on! When all is said and done there is still the LifeStyle system to fall back on :lmao:

 

[Zilch]

Have the Altec drivers you measured been remagnatized??????

No, but I'm unconvinced that any ever need it unless they've been really abused:

http://audioheritage.org/vbulletin/showthread.php?p=110522#post110522

The diaphragms may be suspect, tho. We'll see....

None of mine have, The 806A's have never been opened and the 808-8A have new Radian 1228 diaphragms in them.

I tested the Radians in 804A motors. They have their own problems, and the HF extension they provide is only at VHF; the fundamental rolloff problem remains.

http://audioheritage.org/vbulletin/showthread.php?p=156257#post156257

Neither setup sounded bad (actually pretty good) when used on the 511 with the A7 bass bin, but both are painful (literally) on the 811. I don't want it to be so, but I think the 800 series drivers from Altec are lacking :tears: . Still holding on to hope that it ain't so :sigh: .

Performance on 811 vs. 511 with respect to HF is nearly identical. The A7's Cabinover heard had the HF augmented with tweeters. The benefit of 511 is that it will play at 800 Hz authoritatively, but not 500 Hz. 811 is a 1.2 kHz horn, not 800 Hz, in my recent experience with it....

While you may be stepping on toes here, carry on! When all is said and done there is still the LifeStyle system to fall back on :lmao:

Standards change as technology advances the state of the art. The presumption that 50-year-old gear is up to the challenge is subject to verification. In this case, it doesn't seem to be happening....

 

[Redboy]

HUH? Now's the time to tune your boxes and listen to their new bass!

Well...

I'm not exactly sitting around waiting. Been a little housebound with a sick kid lately, but during naptime I've been sneaking out to the garage to start refurbing the cabs. Sanding down the scratches now, and I'm pretty pleased with how it's coming along. I'm not sure what to do with those fabulous grilles, though. I thought about hitting them very lightly with fine grit on a sanding block. I'm also wondering if the backsides might be more presentable than the fronts - there are some chips and scratches on front... time to remove those baffles and find out!

There I go again, getting hung up on aesthetics! I guess that's as important to me as it is to my wife!

 

[Redboy]

These are cleaning up nicely!

Here's how things are shaping up...

I'm disappointed that I didn't take better "before" pictures of the tops and sides of the cabinets, but you'll have to trust me that they were fairly well scratched up.

I'm pretty happy. They have only been rough sanded at this point and should should look really great with some Danish oil on them.

The grilles have only one presentable side, after all. I'm going to sand them lightly with fine grit and clean out the years of caked dust and what appears to be furniture wax.

Check this out: